blue blood also blue·blood (blblŭd′)
1. Noble or aristocratic descent.
2. A member of the aristocracy.
[Translation of Spanish sangre azul : sangre, blood + azul, blue (probably from the visible veins of fair-complexioned aristocrats).]
blue-blooded (-blŭd′ĭd) adj.
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2020 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Indo-European & Semitic Roots Appendices
Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:
The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.